1. Field of the Invention
The present invention relates to a hydraulic brake of a bicycle and, more particularly, to an oil pipe connection device for a hydraulic brake of a bicycle and having a simplified structure and an excellent sealing effect.
2. Description of Related Art
A hydraulic brake device for a bicycle substantially comprises a brake lever, a disk brake and an oil pipe. The brake lever is mounted on a handlebar of the bicycle, and the disk brake is mounted on a side of a wheel of the bicycle. The oil pipe is connected between the brake lever and the disk brake to lead oil from the brake lever to the disk brake to provide a braking effect to the wheel. To connect the oil pipe securely with the brake lever or disk brake, different connection devices are provided.
With reference to FIG. 6, a conventional connection device 90 for an oil pipe comprises a base 80, an oil pipe 91, a pipe connector 92, a pressing ring 93 and a securing nut 94. The base 80 is formed as a part of a brake lever and has a connection hole 81 formed in the base 80. The oil pipe 91 is connected with the base 80. The pipe connector 92 is inserted into the oil pipe 91 and has a head 922, an insertion segment 921 and an O-ring 924. The head 922 is formed on one end of the pipe connector 92 and has an annular groove 923 defined around the head 922. The insertion segment 921 is formed on and protrudes from one side of the head 922, is inserted into the oil pipe 91 and is composed of multiple conical collars. The O-ring 924 is mounted in the annular groove 923 in the head 922. The pressing ring 93 is mounted around the oil pipe 91. The securing nut 94 is screwed with the connection hole 81 in the base 80 and holds the pressing ring 93 inside. With the securing nut 94 and the clamping effect provided by the pressing ring 93, the oil pipe 91 is connected with the connection hole 81 in the base 80. The O-ring 924 provides a sealing effect to prevent the oil in the base 80 from leaking.
However, the conventional connection device 90 has the following drawbacks.
1. The conventional connection device 90 composed of a pipe connector 92, an O-ring 924 and a pressing ring 93 has a lot of components, so to assemble the conventional connection device 90 is laborious and troublesome. The cost for manufacturing and assembling the conventional connection device 90 is high, and some component may be easily missed or assembled in an opposite direction.
2. The O-ring 924 is made of a rubber material but is easily deformed or broken during the assembling process of the conventional connection device 90 if interference between the components occurs. The sealing effect provided by the O-ring 924 is easily lost due to becoming aged or deteriorated after a period of use.
3. The O-ring 924 is mounted in the annular groove 923 in the head 922 of the pipe connector 92, but the size of the pipe connector 92 is relatively small. Therefore, to form the annular groove 923 in the head 922 of the small pipe connector 92 is difficult, and the O-ring 924 is easily detached from the annular groove 923 to lose the sealing effect.
To overcome the shortcomings, the present invention provides an oil pipe connection device to mitigate or obviate the aforementioned problems.